Internal-combustion engine



March 10, 1931;. I R. c. MACUMBER" 1,795,726

INTENAL COMBUSTION ENGINE Filed'may 51. 192B- 2 sheets-sheet 1 RALDH CMAcuMBER v www N.

March 10, 1931. R. C, MACUMBER 1,795,726

INTERNAL COMBUSTION ENGINE Filed May 51. .1928 2 sheets-Sheet 2 Z7 Y Z8 gva/vento@ 2&4' f RALPH CMACUMBER 61H01 n aq Patented Mar. 10, 1931 UNV'D STATES RALPH C. MACUMBER,

OF PORTLAND, MAINE INTERNAL-COMBUSTIN ENGINE Application led May 31,

This invention relates to internal combustion engines. v

In the designing and manufacturing of two-stroke cycle engines, it has been found difficult to admit the explosive mixture into a cylinder at some time other'than that at which the previously fired charge is exhausted from the cylinder, the result being that some of the fresh charge is exhausted with the red charge. It also has been found difficult to properly effect compression of the incoming charge so as to derive the greatest efficiency from the explosion of the charges. In the manufacture of internal combustion engines in general, it has been the common practice to provide valve means for controlling the passage of fresh charges into and exhaust charges from the cylinder, such valve means usually requiring the use of cam shafts, chains, push rods, etc. Italso has been the common practice to compress a given charge of the explosive mixture once previous to firing the charge, the compression of the charge taking place upon upward movement of the piston of aI working y cylinder.

An important object of the present invention is to provide a novel internal combustion enginemof the two-strokek cycle type wherein many of the disadvantages of prior types have been eliminated, thus increasing the efficiency of the motor.

A further object is to provide an internal combustion engine whereinV 'an extremely high compression ratio is obtained by means of novel compressing means associated with the working cylinders.

A further object is to provide a valveless engine of the two-stroke cycle type wherein a high compression ratio is obtained and wherein the explosive charges are admitted Ainto the working cylinders after the completion of the previously fired charges.

A further object is to provide a motor of the character referred to wherein alternate cylinders and pistons are provided for compressing and firing the charges, the cylinders andpistons being` substantialduplicates of each other.

A further object is to provide an internal 192s. serial No. 281,979.

combustion engine of the character referred to wherein the desiredresults are obtained without the use of the usual types of valves and operating means therefor, thus matef rially simplifying the construction and rendering its manufacture more economical, as well as eliminating sources of trouble usually found in devices of this character.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the drawings I have shown one embodiment of the invention. In this showing,

y Figure 1 is al sideelevation, 'Figure Q is an end elevation, y

Figure?) is a centralvertical longitudinal sectional view, l)arts being shown in elevation,

Figure 4 is a section on line fm1 of Figure 1, and,

Figure 5 is a detail perspective view of one ofthe pistons. y

' Referring to the drawings the numeral 1() designates vacylinder block as a whole closed at its topb'y a head 11 secured thereto by bolts 12. Any type of cylinder block and associated elements may be employed, so far as the present vinvention is applicable to standard practice, and in the present instance, the cylinder block is shown as being provided with a lower flange 13 bolted as at 14 to a crank case 15 comprising upper and lower complementary portions 16-and 17. The sections of the crank case are bolted together as at 18. Ther cranlr case carries a plurality "of bearings 19, *thel outer bearings being supported bythe end walls of the crank case while the inner bearings are carried by suitable webs 20. Eachhearing is provided with the usual bushing 21, and acrank shaft 22 is rotatable in these bushingsin the usual manner. The crank shaft is provided with the usual cranks 23, and a fly wheel 24 is mounted upon one end of the crank shaft, as shown in Figure 3.

The cylinder block may be provided with any suitable number of cylinders as will be apparent, and in the present instance, four cylinders 25, 26,- 27 and 28 are illustrated. rIhe cylinders 25 and 27 are compression cylinders while the cylinders 26 andv 28 are tiring chambers, as will be explained, a second stage of compression taking place in the lat-ter cylinders. The cylinder head 11 is provided with a Cylindrical depending projection 29 extending into each of the cylinders coaxially with respect thereto. These projections are preferably hollow to provide water spaces 30 which communicate with a water jacket 3l formed in the cylinder head. This water liacket also communicates with a water jacket 32 formed in the cylinder block.

Pistons 33 and 34 reciprocate in the cylinders 25 and 27 respectively, while similar pistons 35 and 36 reciprocate in the firing cylinders 26 and 28. The pistons are inverted with respect to the usual types of pistons, each piston being provided with an upwardly extending` skirt 37. It will be apparent that the projections 29 of the cylinder heads are smaller in diameter than the cylinders thus providing an annular space into which the skirts of the piston extend upon each upward reciprocation of the latter. The compressor pistons 33 and 34 are provided in one side with ports 38, formed near the bottom of the pistons while the pistons 35 and 36 are provided with admission ports 39 spaced a material distance above the bottom of the piston for a. purpose to be described.

One of the compressor pistons is shown in detail in Figure 5 of the drawings, this piston being identical with the remaining pistons except that those mounted in the firing cylinders are provided with the ports 39 previously described. Each of the pistons is provided with sealing rings 40, preferably arranged beneath the skirts 37. A wristpin 4l is carried by each piston for connection with the upper end of a piston-rod 42, the lower end of each piston rod being connected to one of the cranks 23 in the usual manner.

Referring to Figures 3 and 4, the numerals 43 and 44 designate intake ports formed in the cylinder block and communicating respectively with the cylinders 25 and 27. The admission ports referred to are arranged in such position that they will be cleared by the pistons 33 and 34 when the latter are at their lowermost positions, the piston 33 being illustrated in such position in Figure 3. Explosive charges are supplied to the admission ports by a manifold 45 provided with an intake pipe 46 connected to a carbureter of any desired type. The contacting surfaces of the manifold and the cylinder block may be machined, and the manifold is secured in position by screws 47 threaded in openings 48 formed in the cylinder block.

As previously stated, the ring of the charges takes place in the cylinders 26 and 28, the exhaust gases passing from these cylinders respectively through exhaust ports 43 and49. These exhaust ports communicate with an exhaust manifold 50 having an outlet pipe 5l which may be `connected tothe usual muffler. The contacting surfaces of the cylinder block and the exhaust manifold also may be machined, and the manifold is secured in position by screws 52 threaded in suitable openings 53 formed in the cylinder block. It will be apparent that gaskets may be eniployed between the cylinder block and the intake and exhaust manifolds.

Communication is adapted to established between each compression cylinder and its associated firing cylinder through ports 54 formed in the cylinder walls between the compression and firing cylinders. This communication is established when the pistons reach the position indicated by the pistons 34 and 36 in Figure 3. Y

The explosive charges are adapted to be fired by any suitable means, and in the present instance, the head il is shown as being provided with threaded openings 55 in which are arranged spark plugs 56 of the usual type.

Y The operation of the two sets of compression and firing cylinders is the same', and only one need be referred to in detail.4 As the piston 33moves downwardly, a depresison will be created in the cylinder 25, and as soon as the upper end of the skirt 37 of this piston clears the port 43, an explosive charge will be drawn into the cylinder 25, this charge being created by the usual carbureter and supplied to the cylinder through the. manifold 45. Communication with the manifold will be out off as soon as the piston 33 moves upwardly a relatively short distance, and further movement of this piston to the upper limit of its movement compresses the charge in the cylinder 25. The full compression of the charge will be effected when the pist-on reaches the same position as the piston 34, as

illustrated in Figure 3, the downwardly pro- :105

jccting member 29 reducing the cubic capacity of the cylinder to effect the desired compression. When this position of full compression is reached, the port 38 will register with the port 54 formed in the cylinder wall and the piston 35 will be in the Vertical position shown in Figure 3 with the port 39 iu registration with port54, and thus the ei;- plosive charge compressed in the cylinder will pass under pressure into the cylinde;` 26r This action will take place with the piston 35 in the vertical position shown in Figure 3, as previously stated, with the corresponding crank 180 from the position shown with .the piston moving upwardly. Thus thc charge admitted into the cylinder 26 will be subjected to a secondV stage of compression upon upward movemcntof the piston 35, and the charge will be fired when the latter piston reaches a point adjacent its upper limit of movement, depending upon the adjustment of the ignition system.

The explosion of the charge forces the piston 35 downwardly, but the explosive charge cannot return to the cylinder 25 when the piston 35 reaches the position shown in Figure 3 for the reason that the compressor piston 33 will be at the bottom of its stroke and its sleeve 37 will close the port 34. Thus the expansion of the explosive charge will continue in the cylinder 26 and the piston 35 will be forced downwardly until it reaches a point adjacent its lower lilnit of movement, at which time the upper edge of the sleeve 37 of the piston 35 will uncover the port 48 to exhaust the burned gases from the cylinder 26.

The same action takes place in the cylinders 27 and 28. During each complete reciprocation of the compressor pistons, a charge of explosive mixture will be drawn into the corresponding cylinder, the charge willbe compressed, and at the proper time, the charge will pass under pressure into the adjacent firing cylinder. During each complete reciprocation of either of the pistons 35 and 36, the port 54 will be uncovered to admit the explosive charge, the charge will be compressed and then fired, and finally the exhaust port will be uncovered to scavenge the cylinder.

From the foregoing it will be apparent that a. two-stroke cylinder engine is provided whereby an explosive charge is fired at each downward movement of the pistons of the tiring cylinders, and the explosive charge is subjected to two stages of compression before the firing action occurs. It also will be apparent that the admission of fresh charges and the exhausting of burned charges take place at different times, thus preventing the loss of fresh charges through the exhaust ports as usually occurs with the standard types of two-cycle engines. The firing of the highly compressed charges effects a more efficient chemical action as each explosion takes place, and thus the efficiency of the motor is greatly increased. The various functions of the parts referred to take plaoewithout the use of any additional elements such as valves, cam shafts, push rods, etc., and thus the motor may be economically manufactured and is so simple in construction as to minimize the danger of engine trouble of various kinds.

The cranks of the two compression pistons are preferably arranged 180 apart when an engine of the type illustrated is employed, and similarly, the cranks of the firing pistons also are arranged 180O apart. Thus, two explosions per revolution of the crank shaft will occur in an engine` of the type illustrated, corresponding to the usual action of a four cylinder four-stroke engine. The crank of each compression piston preferably is arranged substantially 90 from the crank of the corresponding firingl cylinder in order to secure the most efficient results.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement .of part-s may be resorted to wit-hout departing from the spirit of the invention or the scope of the subjoined claims.

I claim:

l. An internal combustion engine comprising a pair of cylinders khaving a passage affording communication therebetween, a piston vreciprocable in each of said cylinders, a shaft having cranks connected to said pistons, said pistons being provided with ports adapted to simultaneously register with said passage once during each cycle of movement, and means for firing a charge in one of said cylinders, said last named cylinder being provided with an exhaust port, the other of said cylinders being provided with an intake port for the admission of explosive mixture, said pistons comprising the sole means to control the movement of gases through said ports, whereby said passage is opened a substantial length of time after the opening of said exhaust port. f

2. An internal combustion engine comprising a pair of cylinders having a passage affording communication therebetween, a piston reciprocable in each of said cylinders and provided with an upturned skirt portion, said skirt portions being provided with ports ladapted* to simultaneously register with said passage once during each cycle of movement, and means for firing a charge in one of Said cylinders, said last named cylinder being provided with an exhaust por-t, the other of said cylinders Ybeing provided with an intake port for the admission of explosive mixture, the skirt portions of said pistons comprising the 'sole means to control the movement of gases through said ports, whereby'said passage is opened a substantial length of time after the opening of said exhaust port. i

3. vAn engine constructed in accordance with claim 2 provided with stationary means adapted to displace gases from said skirt portions as said pistons move upwardly.

4. An internal combustion engine comprising a firing cylinder and an explosive mixture compression cylinder having a passage adapted to afford communication therebe- A tween, a piston reciprocable in each of Said cylinders and provided V*with an upturned skirt portion, said skirt portions being provided with ports adapted to simultaneously register with said passage when the piston of said compression cylinder is near the top of its stroke and the other piston is moving upwardly, a shaft having cranks connected to.

said pistons, and means for firing a charge in said firing cyhnder,sa1d compression and firing cylinders being provided with intake and.

exhaust ports respectively adapted to be uncovered by the skirt portions of said pistons when the latter are near their lower limits of movement.

.t-An engine constructedV in accordance withclaim et provided with stationary means adapted to displace gases from the skirt portions of said pistons as the latter move up- 6. An engine constructed in accordance with claim 4 wherein said cylinders are closed at their upper ends by a head, and projections carried by said head and depending axially into said cylinders to displace gases from the skirt portions of said pistons as the latter move upwardly.

7. An internal combustion engine comprising a firing cylinder and an explosive mixture compression cylinder having a passage adapted to afford communication therebetween, a piston reciprocable in each of said cylinders and provided With an upturned skirt portion, said skirt portions being pro- O vided with ports adapted to simultaneously register' with said passage when the piston in said compression cylinder is adjacent the top of its stroke, and the other piston is 'moving upwardly, a common shaft havin cranks connected to said pistons, said cran s being substantially 90o apart, and means for firing a charge in said firing cylinder, said compression and firing cylinders being provided with intake and exhaust ports respectively 3.0 adapted to be uncovered by the skirt portions of said pistons when the latter are near their lower limits of movement. Y

8. An internal combustion engine comprising a iiring cylinder and an explosive mixture compression cylinder having a passage adapted to aiford communicationV therebetween, a piston reciprocable in each cylinder and adapted to simultaneously uncover said passage, a shaft having cranks connected to o said pistons and spaced apart whereby the uncovering of said passage takes place when the piston of said compression cylinder is near they top of its stroke and the other piston is intermediate the length of its upward 5 stroke, and means for iring a charge in said firing cylinder, said compression and firing cylinders being provided with intake and eX- haust ports respectively adapted to be uncovered by the skirt portions of said pistons when the latter are near their lower limits of movement. l

In testimony whereof I aiiix my signature.

RALPH C. MACUMBER. 

